1. Field of the Invention
The present invention relates to a recording apparatus with a transfer inkjet recording system.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2009-045885 discloses a recording apparatus with a transfer inkjet recording system. In the recording apparatus, an intermediate image (i.e., an ink image) is once formed on an intermediate transfer medium by an inkjet method, and then the formed intermediate image is transferred to a recording medium. Since ink viscosity of the intermediate image is important for good transfer, ink viscosity is increased by heating the intermediate image formed on the intermediate transfer medium by, for example, a heater so as to let an ink solvent evaporate. In the apparatus disclosed in Japanese Patent Laid-Open No. 2009-045885, a surface of the intermediate transfer medium is cooled by applying a coolant after the transfer. Formation of images on the recording medium is repeated by a series of processes of forming an intermediate image, heating, transferring and cooling is repeated as one recording cycle.
FIG. 1A illustrates, in a sectional view, heating of a high duty region (which is a region in which a surface of an intermediate transfer medium is covered densely by ink) in an intermediate image. Most of the heat W (represented by a bold arrow in FIG. 1A) applied from above by a heater is taken away as the heat of evaporation for the evaporation of an ink solvent with a coloring material left. For this reason, the intermediate transfer medium itself is not heated excessively and thus temperature rise is slow. On the contrary, as illustrated in FIG. 1B, when the heat W is applied to a low duty region (which is a region in which the surface of the intermediate transfer medium is covered less densely by ink) in the same intermediate image, the amount of heat of evaporation during the evaporation of the ink solvent is small; thus a greater amount of heat is transferred to the intermediate transfer medium than the configuration illustrated in FIG. 1A, and thus temperature rise is steep. With this mechanism, even in the same intermediate image formation region, difference in temperature occurs between the surface of the intermediate transfer medium in the high duty region and the surface of the intermediate transfer medium in the low duty region after a heating process. The difference in temperature exists in subsequent recording cycles.
The difference in temperature is not eliminated in a short time even if the intermediate transfer medium is cooled after the transfer process as in the configuration disclosed in Japanese Patent Laid-Open No. 2009-045885. If the subsequent recording cycle is begun with the difference in temperature has not been eliminated, “insufficient transfer” is more likely to occur in the mechanism described below.